Dividing by zero is not legal. Depending on how the divisor subexpression is evaluated, one of following errors occurs:

If the divisor subexpression that evaluates to zero is a constant, the error appears at design time, causing the expression to fail validation.

If the divisor subexpression that evaluates to zero contains variables, but no input columns, the component to which the expression belongs fails the pre-execution validation that occurs before the package runs.

If the divisor subexpression that evaluates to zero contains input columns, the error appears at run time and is handled according to the error flow rules of the data flow component.